China proper, also called Inner China, are terms used primarily in the Western world in reference to the traditional "core" regions of Chinese civilization centered around the Yellow River and Yangtze River valleys. There is no fixed definition for China proper as many administrative, cultural and territorial shifts have occurred throughout history. One definition refers to the original heartland regions of the Chinese civilization, the Central Plain as well as the historical Nine Provinces; another to the Eighteen Provinces inside Shanhai Pass designated by the Qing regime. In contrast, Outer China is a term usually includes the peripheral marchland regions such as Gobi Desert,, Tarim Basin, Northeast China, Dzungaria, Tibetan Plateau, and Yungui Plateau, which were historically autonomous regions with unstable allegiance to the authority of Chinese monarchs.